1. Technical Field
The present invention relates to an image processing device, an image display device, and a projector for performing image processing on an image signal.
2. Related Art
An image processing LSI provided to an image display device and so on is connected to an external frame buffer (frame memory) as a storage device composed of a DRAM or the like, and performs a variety of image processing while storing the image signal into the frame buffer. Since the band frequency (the data transfer capacity) of the frame buffer becomes insufficient if the process using the frame buffer increases due to sophistication in function of the image display device, there has been used in recent years the technology of compressing the image signal before writing the image signal into the frame buffer in order for reducing the data amount to be transferred to the frame buffer (see, e.g., JP-A-2010-183328).
However, if the image signal is compressed, the higher the compression ratio is, the more the image is deteriorated. Therefore, if priority is given to the image quality, since it is not allowed to set the compression ratio to so high, the sufficient band frequency of the frame buffer might fail to be provided depending on the use environment, the operation circumstances, and so on. On the other hand, if the bus width is expanded or the clock frequency is raised in order to provide the sufficient band frequency, the necessary number of DRAMs might increase or expensive DRAMs might be required, and therefore, the price of the device might rise. As described above, in the image processing LSI having the configuration of the related art, it is difficult to efficiently perform the image processing using the frame buffer.